Costs Lawyers and PI insurance: what the CLSB requires
Reviewed by Matthew Bartlett, Director, Apex Insurance Brokers Limited · Last reviewed 2026-08-05
In short: The Costs Lawyer Standards Board (CLSB) requires every practising Costs Lawyer to hold adequate professional indemnity insurance (PII) as a condition of their practising certificate, under its Practising Rules. The rules set out that cover must be in place; they do not publish widely-circulated fixed figures, so you should confirm the current minimum terms and limit directly with the CLSB.
If you are a Costs Lawyer regulated by the Costs Lawyer Standards Board, professional indemnity insurance is not optional. It sits alongside your practising certificate as one of the conditions that keeps you entitled to practise. This page explains where the requirement comes from, what it is designed to do, and the practical questions to settle before you renew or arrange cover.
Who regulates Costs Lawyers
Costs Lawyers are a regulated legal profession in England and Wales. The approved regulator is the Association of Costs Lawyers (ACL), and independent regulatory functions are carried out by the Costs Lawyer Standards Board (CLSB) under the framework of the Legal Services Act 2007. In practice, it is the CLSB that authorises Costs Lawyers, issues practising certificates and sets the conduct and practice rules you must follow.
That structure matters for insurance. Because the CLSB is your regulator, it is the CLSB Practising Rules — not the SRA Minimum Terms and Conditions, and not the Bar's arrangements — that govern the PII you must hold. Requirements written for solicitors or barristers do not automatically apply to you, and cover designed for another profession may not meet your obligations.
What the CLSB requires
The core position is straightforward: a practising Costs Lawyer must have professional indemnity insurance in force. It is a condition of holding a practising certificate, and the CLSB expects you to be able to demonstrate that cover is in place when you apply or renew.
The purpose is consumer protection. If your professional work — costs budgeting, drafting bills, points of dispute, detailed assessment advocacy, negotiation — causes a client financial loss through an error or omission, PII is the mechanism that allows that client to be compensated without your personal finances or your firm being the only backstop.
Because published figures for the exact minimum are not widely circulated, treat the following as the shape of the obligation rather than a fixed number:
- Cover must be adequate and appropriate to the nature and scale of your practice — a sole practitioner handling occasional files and a busy costs firm are not in the same position.
- It must be current and continuous. A gap in cover is a gap in your ability to practise, not merely an administrative oversight.
- It must respond to your actual work. If you have broadened into new areas or taken on higher-value matters, your limit and terms should keep pace.
Get a professional indemnity quote built around your Costs Lawyer practice →
Confirm the current figures with the CLSB
We deliberately do not quote a specific minimum limit or wording requirement on this page. Regulatory minimums can be reviewed and changed, and stating an out-of-date figure could lead you to under-insure. Before you buy or renew, check the current CLSB Practising Rules and any accompanying guidance for:
- the minimum level of indemnity you must carry;
- any required policy features or minimum terms;
- how the requirement is expressed — for example a flat limit, or a limit that scales with the size or turnover of your practice;
- whether run-off cover is expected when you stop practising or close your firm.
If in any doubt about what applies to your circumstances, the CLSB is the authoritative source. A good broker will then translate that requirement into a policy that meets it.
What a Costs Lawyer PII policy typically covers
Professional indemnity insurance for Costs Lawyers is built to respond to claims arising from your professional services. Typical features include:
| Feature | What it means for you |
|---|---|
| Civil liability cover | Responds to claims for loss caused by a negligent act, error or omission in your costs work. |
| Defence costs | Legal costs of investigating and defending a claim, which can be significant even where the claim ultimately fails. |
| Choice of limit | Illustrative options such as £1m, £2m or £5m any one claim — set to meet the CLSB minimum and the exposure on your largest matters. |
| Retroactive cover | Protection for past work, provided you have maintained continuous cover with no unfilled gaps. |
| Run-off cover | Continues to protect you after you stop practising, since claims can surface years after the work was done. |
PII is almost always written on a claims-made basis. That means the policy that responds is the one in force when the claim is made against you, not the one in force when you did the work. This is precisely why continuous cover and, in due course, run-off cover matter so much — a lapse can leave historic work exposed.
Arranging or renewing cover that meets the CLSB Practising Rules? We can help you get the limit and terms right.
Get a PI quote →Setting the right limit for your practice
Meeting the regulatory minimum is the floor, not the target. The right limit reflects the value of the matters you handle and the loss a client could suffer if something went wrong. A Costs Lawyer who routinely deals with high-value costs claims, budgeting on substantial commercial litigation, or advocacy at detailed assessment may carry exposure well above any baseline minimum.
When reviewing your limit, think about the size of your largest single matter, whether you are a sole practitioner or part of a firm, and how your practice has changed since the last renewal. If your work has grown, your cover should be reviewed rather than simply rolled over.
Common questions
Do all practising Costs Lawyers need PII?
Yes. Holding professional indemnity insurance is a condition of your practising certificate under the CLSB Practising Rules. If you are authorised to practise as a Costs Lawyer, you need cover in force.
What is the minimum level of cover?
The CLSB sets the requirement, and the exact figure is best confirmed directly with the CLSB, as it can be reviewed over time. We do not quote a fixed minimum here to avoid giving an out-of-date number — check the current Practising Rules and set your limit at or above that level.
Do I need run-off cover when I retire or close my practice?
Almost certainly. Because PII is claims-made, a claim about work you did years ago could still arise after you stop practising. Run-off cover keeps that historic work protected. Confirm the CLSB's expectations and speak to your broker before you cease practice.
Talk to Apex about PI cover for Costs Lawyers →
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This guide is general information, not advice on a specific policy or a substitute for your policy wording.